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<h1>Ordering</h1>

<p>This tab allows you to decide:

<p><b>the counterbalancing strategy</b> (latin square, random or all pairs), to determine how trials and blocks are ordered for each subject. Note that latin square or all pairs strategies require a given number of participants. For example, suppose that a block is defined by the interaction technique (TQ) and the difficulty of the task (Diff) and there are 3 different interaction techniques and 2 levels of difficulty. In this case, a Latin Square computes 6 different orders imposing a number of subjects that is a multiple of 6 ; and a all pairs strategy computes 6! different orders imposing a number of subjects that is a multiple of 6!. The random strategy does not require any particular number of subjects but is less safe for avoiding potential presentation order effects.</p>

<p><b>the order for presenting replications</b>, i.e. choose whether trial/block replications are serial or distributed within a block.</p>

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